Six-Year Incidence of Visual Impairment in a Multiethnic Asian Population: The Singapore Epidemiology of Eye Diseases Study

Zhi Wei Lim; Miao-Li Chee; Zhi Da Soh; Shivani Majithia; Thakur Sahil; See Teng Tan; Charumathi Sabanayagam; Tien Yin Wong; Ching-Yu Cheng; Yih-Chung Tham

doi:10.1016/j.xops.2023.100392

Six-Year Incidence of Visual Impairment in a Multiethnic Asian Population: The Singapore Epidemiology of Eye Diseases Study

Ophthalmol Sci. 2023 Sep 3;3(4):100392. doi: 10.1016/j.xops.2023.100392. eCollection 2023 Dec.

Authors

Zhi Wei Lim^{1

2}, Miao-Li Chee², Zhi Da Soh², Shivani Majithia², Thakur Sahil², See Teng Tan², Charumathi Sabanayagam^{2

3}, Tien Yin Wong^{2

4

5}, Ching-Yu Cheng^{1

2

3

6}, Yih-Chung Tham^{1

2

3

6}

Affiliations

¹ Yong Loo Lin School of Medicine, National University of Singapore, Singapore.
² Singapore Eye Research Institute, Singapore National Eye Centre, Singapore.
³ Eye Academic Clinical Program, Duke-NUS Medical School, Singapore.
⁴ Tsinghua Medicine, Tsinghua University, Beijing, China.
⁵ School of Clinical Medicine, Beijing Tsinghua Changgung Hospital, Beijing, China.
⁶ Centre for Innovation and Precision Eye Health & Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore.

Abstract

Purpose: To examine the 6-year incidence of visual impairment (VI) and identify risk factors associated with VI in a multiethnic Asian population.

Design: Prospective, population-based, cohort study.

Participants: Adults aged ≥ 40 years were recruited from the Singapore Epidemiology of Eye Diseases cohort study at baseline. Eligible subjects were re-examined after 6 years. Subjects included in the final analysis had a mean age of 56.1 ± 8.9 years, and 2801 (50.5%) were female.

Methods: All participants underwent standardized examination and interviewer-administered questionnaire at baseline. Incidences were standardized to the Singapore Population Census 2010. A Poisson binomial regression model was used to evaluate the associations between baseline factors and incident presenting VI.

Main outcome measures: Incident presenting VI was assessed at the 6-year follow-up visit. Visual impairment (presenting visual acuity < 20/40), low vision (presenting visual acuity < 20/40 but ≥ 20/200), and blindness (presenting visual acuity < 20/200) were defined based on United States definition.

Results: A total of 5551 subjects (2188 Chinese, 1837 Indians, and 1526 Malays) were evaluated, of whom 514 developed incident presenting VI over 6 years. Malays had a higher incidence of low vision and blindness (13.0%; 0.6%) than Indians (7.0%; 0.1%) and Chinese (7.7%; 0.2%). Among Malay individuals with VI at baseline, 52.8% remained visually impaired after 6 years, which was considerably higher than Chinese (32.4%) and Indians (37.2%). Older age (per decade; relative risk [RR] = 1.59), a history of cardiovascular disease (RR = 1.38), current smoking (RR = 1.31), smaller housing type (1- to 2-room public flat; RR = 2.01), and no formal education (RR = 1.63) at baseline were associated with a higher risk of incident VI (all P ≤ 0.027). Older age (> 60 years) contributed the highest population attributable risk to incident VI (27.1%), followed by lower monthly income (Singapore dollar < $2000; 26.4%) and smaller housing type (24.7%). Overall, undercorrected refractive error (49.1%) and cataract (82.6%) were leading causes for low vision and blindness, respectively. This was consistently observed across the 3 ethnicities.

Conclusions: In this multiethnic Asian population, Malays had a higher VI incidence compared to Indians and Chinese. Leading causes of VI are mostly treatable, suggesting that more efforts are needed to further mitigate preventable visual loss.

Financial disclosures: The authors have no proprietary or commercial interest in any materials discussed in this article.

Keywords: Asia; Blindness; Incidence; Low vision; Vision impairment.